if i list something for 4 favors, and the minimal listing fee is 10 favors, then do i lose favors by selling it? and what happens to any listing fee if the item doesnt sell?

yes you do and the listing fee is gone as soon as you list it

Yes, if it doesnt sell, you still lose it

The key is to sell several of the same amen at a time

The maximum you can fetch for 66 favors

okay well I just noticed if I sell several sw for example like 2000, my price I sell them is say 1800 and im charged over 30,000$ listing fee BECAUSE im selling a bunch of them. Is that a glitch? or is it different for favors?

NO its the way its works. If you list 10 amens for 5 favors it will only cost you 10 favors as the total price of favors isnt over the 10 favor min listing fee